Small reservoirs depth-area-volume relationships in Savannah Regions of Brazil and Ghana

Abstract

In the last years, hundreds of small reservoirs were built in the Savannah regions of Brazil and Ghana. They play an important role in supporting the local economies. The lack of technical information about the small reservoirs in these regions is endangering the sustainability of agriculture and the livelihood of farmers. The purpose of this study was to establish the volume-area-depth relationship for small reservoirs in the Brazilian and Ghana Savannah regions. Thus, a comprehensive field work was performed. In total, 28.5% and 39.0% of the total number of small reservoirs in the Preto River Basin in Brazil and in the Upper East Region of Ghana, respectively, were visited and measured. The results showed a good-fit for the depth-volume and area-volume relationships for both regions, with coefficient of determination, for both cases and both regions, higher than 0.93. The mean k and α1 values were lower in Brazil as compared to Ghana and k1 and α were higher. The values of the parameters presented great variability, indicating the importance of performing local measurements.